package com.zbangmall.util.common;


import java.util.*;

public final class RandomUtil {
	public static final String ALLCHAR
			= "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	public static final String LETTERCHAR
			= "abcdefghijkllmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	public static final String NUMBERCHAR
			= "0123456789";


	/**
	 * 生成制定范围内的随机数
	 *
	 * @param scopeMin
	 * @param scoeMax
	 * @return
	 */
	public static int integer(int scopeMin, int scoeMax) {
		Random random = new Random();
		return (random.nextInt(scoeMax) % (scoeMax - scopeMin + 1) + scopeMin);
	}

	/**
	 * 返回固定长度的数字
	 *
	 * @param length
	 * @return
	 */
	public static String number(int length) {
		StringBuffer sb     = new StringBuffer();
		Random       random = new Random();
		for (int i = 0; i < length; i++) {
			sb.append(NUMBERCHAR.charAt(random.nextInt(NUMBERCHAR.length())));
		}
		return sb.toString();
	}

	/**
	 * 返回一个定长的随机字符串(只包含大小写字母、数字)
	 *
	 * @param length 随机字符串长度
	 * @return 随机字符串
	 */
	public static String String(int length) {
		StringBuffer sb     = new StringBuffer();
		Random       random = new Random();
		for (int i = 0; i < length; i++) {
			sb.append(ALLCHAR.charAt(random.nextInt(ALLCHAR.length())));
		}
		return sb.toString();
	}

	/**
	 * 返回一个定长的随机纯字母字符串(只包含大小写字母)
	 *
	 * @param length 随机字符串长度
	 * @return 随机字符串
	 */
	public static String MixString(int length) {
		StringBuffer sb     = new StringBuffer();
		Random       random = new Random();
		for (int i = 0; i < length; i++) {
			sb.append(ALLCHAR.charAt(random.nextInt(LETTERCHAR.length())));
		}
		return sb.toString();
	}

	/**
	 * 返回一个定长的随机纯大写字母字符串(只包含大小写字母)
	 *
	 * @param length 随机字符串长度
	 * @return 随机字符串
	 */
	public static String LowerString(int length) {
		return MixString(length).toLowerCase();
	}

	/**
	 * 返回一个定长的随机纯小写字母字符串(只包含大小写字母)
	 *
	 * @param length 随机字符串长度
	 * @return 随机字符串
	 */
	public static String UpperString(int length) {
		return MixString(length).toUpperCase();
	}

	/**
	 * 生成一个定长的纯0字符串
	 *
	 * @param length 字符串长度
	 * @return 纯0字符串
	 */
	public static String ZeroString(int length) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < length; i++) {
			sb.append('0');
		}
		return sb.toString();
	}

	/**
	 * 根据数字生成一个定长的字符串，长度不够前面补0
	 *
	 * @param num       数字
	 * @param fixdlenth 字符串长度
	 * @return 定长的字符串
	 */
	public static String toFixdLengthString(long num, int fixdlenth) {
		StringBuffer sb     = new StringBuffer();
		String       strNum = String.valueOf(num);
		if (fixdlenth - strNum.length() >= 0) {
			sb.append(ZeroString(fixdlenth - strNum.length()));
		} else {
			throw new RuntimeException("将数字" +
					num + "转化为长度为" + fixdlenth + "的字符串发生异常！");
		}
		sb.append(strNum);
		return sb.toString();
	}

	/**
	 * 根据数字生成一个定长的字符串，长度不够前面补0
	 *
	 * @param num       数字
	 * @param fixdlenth 字符串长度
	 * @return 定长的字符串
	 */
	public static String toFixdLengthString(int num, int fixdlenth) {
		StringBuffer sb     = new StringBuffer();
		String       strNum = String.valueOf(num);
		if (fixdlenth - strNum.length() >= 0) {
			sb.append(ZeroString(fixdlenth - strNum.length()));
		} else {
			throw new RuntimeException("将数字" +
					num + "转化为长度为" + fixdlenth + "的字符串发生异常！");
		}
		sb.append(strNum);
		return sb.toString();
	}

	/**
	 * 每次生成的len位数都不相同
	 *
	 * @param param
	 * @return 定长的数字
	 */
	public static int getNotSimple(int[] param, int len) {
		Random rand = new Random();
		for (int i = param.length; i > 1; i--) {
			int index = rand.nextInt(i);
			int tmp   = param[index];
			param[index] = param[i - 1];
			param[i - 1] = tmp;
		}
		int result = 0;
		for (int i = 0; i < len; i++) {
			result = result * 10 + param[i];
		}
		return result;
	}

	/**
	 * 从指定的数组中随机数组中的某个元素
	 */
	public static <T> T randomItem(T[] param) {
		int index = integer(0, param.length);
		return param[index];
	}

	/**
	 * 实现一个简单的字符串乘法
	 *
	 * @param str
	 * @param multiplication
	 * @return
	 */
	private static String strMultiplication(String str, int multiplication) {
		StringBuffer buffer = new StringBuffer();
		for (int i = 0; i < multiplication; i++) {
			buffer.append(str);
		}
		return buffer.toString();
	}

	/**
	 * 从指定的数组中按照指定比例返回指定的随机元素
	 *
	 * @param param
	 * @param percentum
	 * @param <T>
	 * @return
	 */
	public static <T> T randomItem(T[] param, double[] percentum) {
		int       length   = percentum.length;
		Integer[] ints     = ArrayUtil.doubleBitCount(percentum);
		int       max      = Collections.max(Arrays.asList(ints));
		int[]     arr      = new int[length];
		int       sum      = 0;
		Map       map      = new HashMap(length);
		int       multiple = Integer.parseInt("1" + strMultiplication("0", max));
		for (int i = 0; i < length; i++) {
			int temp = (int) (percentum[i] * multiple);
			arr[i] = temp;
			if (i == 0) {
				map.put(i, new int[]{1, temp});
			} else {
				map.put(i, new int[]{sum, sum + temp});
			}
			sum += temp;
		}
		int indexSum = integer(1, sum);
		int index    = -1;
		for (int i = 0; i < length; i++) {
			int[] scope = (int[]) map.get(i);
			if (indexSum == 1) {
				index = 0;
				break;
			}
			if (indexSum > scope[0] && indexSum <= scope[1]) {
				index = i;
				break;
			}
		}
		if (index == -1) {
			throw new RuntimeException("随机失败");
		} else {
			return param[index];
		}
	}

	/**
	 * 返回一个UUID
	 *
	 * @return 小写的UUID
	 */
	public static String uuid() {
		UUID   uuid = UUID.randomUUID();
		String s    = uuid.toString();
		return s.substring(0, 8) + s.substring(9, 13) +
				s.substring(14, 18) + s.substring(19, 23) + s.substring(24);
	}

	/**
	 * 返回一个UUID
	 *
	 * @return 大写的UUID
	 */
	public static String UUID() {
		UUID   uuid = UUID.randomUUID();
		String s    = uuid.toString();
		String temp = s.substring(0, 8) + s.substring(9, 13) +
				s.substring(14, 18) + s.substring(19, 23) + s.substring(24);
		return temp.toUpperCase();
	}

	/**
	 * 返回一个有序列的uuid编码
	 * 前11位为时间(毫秒)
	 * 中间4位为主机特征码
	 * 剩下的保证其唯一性
	 *
	 * @return
	 */
	public static String squid() {
		Long   date = System.currentTimeMillis();
		String s    = UUID.randomUUID().toString();
		String str  = Long.toHexString(date);
		String result = str + OpslabConfig.HOST_FEATURE
				+ s.substring(17, 18) + s.substring(19, 23) + s.substring(24);
		return result.toUpperCase();
	}
}
